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Two ground wires for one switch, none for another?

4K views 5 replies 4 participants last post by  J. V. 
#1 · (Edited)
We recently moved into a a house (built in 1999) which has had a lot of unskilled "improvements" done to it.

In one of the bathrooms, a photoelectric motion sensor was installed to control the overhead light. We were seeing extremely weird behavior from this sensor, like it was turning on when we turned lights on in the room above it (but when no motion was going on in the bathroom.)

Anyway, yesterday I had the power off in the house so I decided to replace the problematic sensor with a simple switch. (This is the first light switch I've tried replacing; my experience in the past has been limited to replacing receptacles.)

I opened the box, which is a 3-gang box, left-to-right 1) a GFCI outlet, 2) a switch which controls an exhaust fan, and 3) the motion sensor on the far right.

When I looked at the motion detector, I found (to my surprise) that it wasn't grounded. The middle switch (which controls an exhaust fan), on the other hand, had 2 separate green wires attached to the ground screw.

So, in installing the new switch, obviously I wanted it to be grounded. There was no unused free-floating ground wire in the box, so I decided to unhook one of the two ground wires from the middle switch and attach it to the new switch... leaving one of the ground wires attached to the fan switch and the other ground wire attached to the light switch.

Does this sound like a kosher thing to do? Is there a reason why two grounds would need to be attached to a single switch? I'm assuming all ground wires are essentially equivalent?

Also, the simple light switch I installed didn't indicate which screw was supposed to be hot and which was neutral... they both looked exactly the same. The wires attached to the motion sensor were both black (not one black and one white) unlike receptacles I've replaced in the past.

So, I just attached one of the black wires to the top screw and one to the bottom screw. It seems to be working, but I'd love confirmation that I haven't done something terribly wrong. :)

Thanks for any help!
 
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#2 ·
On a single pole switch (on-off) it doesn't matter which wire goes to which screw. It is simple make-break. You are fine there.

The ground wires, are they coming from the same splice? It is possible that when the sensor switch was originally installed, the person didn't know what to do with the ground wire and just added it to the other switch.
 
#4 ·
The ground wires, are they coming from the same splice? It is possible that when the sensor switch was originally installed, the person didn't know what to do with the ground wire and just added it to the other switch.
I'll check, but as I recall there are two separate ground wires coming into the box (as opposed to a single ground being spliced in the box itself.)

Should I be concerned either way?
 
#3 ·
With the motion sensor switches, a lot of time it is the sensetivity that is out of wack. As for the ground wire, it is most likely what John stated. I went over to see a friend of my wife's little brother's remodel, and looking at it, I easily picked out the problem areas, by not doing it professionally.

Most of the DIY jobs that are done, are more of hack jobs that the home owner watches something on T.V. and belives that they can do it also.
 
#6 ·
I would consider attaching a ground to the box if it is metal.
Switches don't have neutrals even though you may see a white wire on it. Switches just open and close the hot wire.
Your scenario sounds good and safe, assuming your receptacle is GFI protected. (Bathroom).
 
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